A kinetic study for the isomerization of α-pinene epoxide over Fe/SBA-15 and Fe/MCM-41 catalysts was developed using a pseudo-homogeneous (polynomial law) and heterogeneous (LHHW formalism with one and two actives sites) models. TEM analysis of Fe/SBA-15 and Fe/MCM-41 showed that the materials have the typical hexagonal organization; FTIR adsorption–desorption of pyridine revealed the presence of Lewis acidity in both Fe/SBA-15 and Fe/MCM-41 catalysts. The presence of Fe³⁺ and Fe²⁺ species was concluded from XPS analysis; however, active site for α-pinene epoxide isomerization was attributed to Fe³⁺. With toluene as solvent, it was found that in both catalysts, the more adequate kinetic model was the unimolecular LHHW model with two active sites of the same type. Apparently, α-pinene epoxide isomerization is much faster over Fe/MCM-41 (5.78 L h⁻¹ g_Fe⁻¹) than over Fe/SBA-15 (1.14 L h⁻¹ g_Fe⁻¹). The activation energy for both Fe catalysts was evaluated using solvents of different polarity. In the case of Fe/MCM-41, the less energetic barrier was observed with toluene (30.99 kJ mol⁻¹), while tert-butanol (13.76 kJ mol⁻¹) was more favorable in the case of Fe/SBA-15 catalyst. Fe/MCM-41 is a very robust catalyst because it can be used up to four times without a significant loss of catalytic activity in comparison with Fe/SBA-15 that only can be used two times. Finally, a reaction mechanism was proposed for the isomerization of α-pinene epoxide over both Fe/SBA-15 and Fe/MCM-41 catalysts.

中文翻译：

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Fe负载MCM-41和SBA-15材料上α-pine烯环氧化物的异构化动力学

使用伪均相（多项式定律）和异相（具有一个和两个活性位点的LHHW形式论）模型，对Fe / SBA-15和Fe / MCM-41催化剂上的α-pine烯环氧化物异构化进行了动力学研究。Fe / SBA-15和Fe / MCM-41的TEM分析表明，材料具有典型的六边形组织。FTIR吸附-吡啶解吸表明Fe / SBA-15和Fe / MCM-41催化剂均存在路易斯酸度。通过XPS分析推断出Fe ³⁺和Fe ²⁺的存在。然而，α-pine烯环氧化物异构化的活性位点归因于Fe ³⁺。用甲苯作为溶剂，发现在两种催化剂中，更合适的动力学模型是具有两个相同类型的活性位点的单分子LHHW模型。显然，在Fe / MCM-41（5.78 L h ^-1  g _Fe ^-1）上，α-pine烯环氧化物异构化要比在Fe / SBA-15（1.14 L h ^-1  g _Fe ^-1）上快得多。使用不同极性的溶剂评估了两种铁催化剂的活化能。在Fe / MCM-41的情况下，甲苯（30.99 kJ mol ^-1），叔丁醇（13.76 kJ mol ^-1）观察到较低的能垒。在Fe / SBA-15催化剂的情况下）更为有利。Fe / MCM-41是一种非常耐用的催化剂，因为与只能使用两次的Fe / SBA-15相比，它可以使用多达四次而不会显着降低催化活性。最后，提出了在Fe / SBA-15和Fe / MCM-41催化剂上α-pine烯环氧化物异构化的反应机理。